Penélope Merino-Montiel

Selective inhibition of the tumour-associated carbonic anhydrase (CA) isoforms IX and XII, which are overexpressed in hypoxic tumours, has emerged as a promising strategy for the development of novel anticancer agents. Among the diverse CA inhibitors reported to date, coumarins have attracted particular attention. These chromenone derivatives, widely distributed in phytochemicals, display a broad range of biological activities and are known to act as suicide inhibitors of CAs. Following the tail approach, we designed a series of hybrid compounds combining a coumarin core with an N-arylthioureido scaffold located at the C-7 position and investigated how structural variations—including substituents on the coumarin and aromatic moieties, tether length, and urea/thiourea isosterism—influence their biological properties (CA inhibition and antiproliferative activity). Substituted coumarins at C-3 and C-4 were efficiently prepared via Pechmann condensation, while the thioureido motif was introduced using various aryl isothiocyanates as key synthetic intermediates. The lead compound, featuring a dimethylated coumarin, a pentyl linker, and an N-(p-tolyl)thioureido residue, inhibited the target enzymes in the low- to mid-nanomolar range (K_i = 6.0 and 49.9 nM, respectively), displaying selectivity indexes (S.I.s) surpassing those of the reference drug acetazolamide (AAZ). Moreover, it exhibited potent antiproliferative activity, with GI₅₀ values in the low micromolar range (1.9–3.5 µM) against both drug-sensitive and multidrug-resistant cancer cell lines. Label-free three-dimensional holotomographic microscopy revealed that this compound triggers slow apoptosis, leading to cell death after approximately 20 h of exposure.

We synthesised coumarin-based derivatives bearing thio- and selenocyanates to selectively inhibit tumour-associated carbonic anhydrases (CAs) IX and XII and to exert antiproliferative effects on tumour cells. Structural variations included chalcogen atom type (S, Se), substitutions at C-3/C-4, and tether length at C-7 of the coumarin core. Thiocyanates 4 and 7b showed potent CA IX/XII inhibition (K_i = 17.9-27.4 nM) with >5000-fold selectivity over off-target isoforms (CAs I and II). Selenocyanate 8a exhibited strong antiproliferative activity (GI₅₀ = 0.78-2.6 µM) across six human solid tumour cell lines. Mechanistic studies revealed a cytostatic effect via cell cycle arrest and reduced mitotic progression. In vivo assays in Caenorhabditis elegans confirmed selective cytostatic action of selenocyanate 8c, reducing tumorous germline size without affecting healthy tissues at therapeutic doses.

A total of 24 novel steroidal derivatives were synthesized, including 1,3,4-thia(selena)diazolines and structurally unique spirothiadiazolines, obtained through intramolecular cyclization under standard acetylation conditions. This strategy was further extended to the construction of a novel dimeric compound bearing a thiadiazoline linker. Seleno- and thiosemicarbazone precursors were derived from various functionalized steroidal monomers and dimers via straightforward synthetic protocols. Key intermediates included aldehyde 7 and ketones 16, 19, and 24. Rotameric equilibria were observed in certain thiosemicarbazones, attributed to partial double-bond character in the N–CS bond. Cyclization yielded heterocyclic systems as epimeric mixtures, and in some cases, inseparable mixtures of isomers were obtained due to low diastereoselectivity. Full structural elucidation of epimeric pairs was achieved using 2D NMR and IR spectroscopy, with compounds 2, 3, 5, 11, 17, 27, 28a, and 28b further confirmed by single-crystal X-ray diffraction. Preliminary antiproliferative assays against human cancer cell lines revealed GI₅₀ values below 10 µM for compounds 21, 22, and 27.

The selective inhibition of key enzymes, such as carbonic anhydrases (CAs IX and XII), which are overexpressed in cancer tissues, has emerged as a promising strategy in cancer research. However, a multitarget approach is often preferred to achieve enhanced therapeutic outcomes. In this study, aryl sulfonamides were conjugated with a thiosemicarbazone moiety to enable dual functionality: the inhibition of CAs and the chelation of metal cations. Several structural factors were systematically modified, including the position of the sulfonamido group, the length of the linker, the nature of the aromatic residue, and the type of substituents. Tumor-associated CAs IX and XII inhibition was evaluated using the stopped-flow CO₂ hydrase assay, and the inhibition constants (K_i) were determined. The most promising compounds were further analyzed through molecular docking simulations. Metal chelation capabilities were evaluated using UV–Vis spectroscopy, while antiproliferative activities were measured using the sulforhodamine B (SBR) assay. Additionally, holotomographic 3D microscopy was employed to investigate the mechanisms of cell death. Sulfonamido-derived Schiff bases were synthesized through a three-step procedure that did not require column chromatography purification: (1) isothiocyanation of amino-sulfonamides, (2) nucleophilic addition of hydrazine, and (3) acid-promoted condensation with different aldehydes (benzaldehydes or pyridine-2-carboxaldehyde). The synthesized compounds exhibited inhibition of CAs in the low nanomolar to submicromolar range, with selectivity largely influenced by structural features. Notably, the m-sulfonamide derivative 5b, bearing a pyridin-2-yl residue, demonstrated potent and selective inhibition of CA IX (K_i = 4.9 nM) and XII (K_i = 5.6 nM). Additionally, it efficiently chelated Fe²⁺, Fe³⁺, and Cu²⁺ and showed promising antiproliferative activity (GI₅₀ 4.5–10 µM). Mechanistic studies revealed that apoptosis was involved in its mode of action. Therefore, the synergistic integration of sulfonamides and thiosemicarbazones represents an effective strategy for the development of multimodal anticancer agents.

New conformationally‐restricted steroids were synthesized by incorporating a spiranic heterocyclic motif at the C‐17 position, using trans ‐androsterone, trans ‐dehydroandrosterone, and estrone as starting materials. A cyclocondensation process with o ‐disubstituted aromatic bis ‐nucleophiles enabled the modification of the structure. In silico calculations were employed to predict the diastereoselectivity and the assignment of the new chiral center stereochemistry. Spiranic derivatives were evaluated in vitro for antiproliferative activity against six human tumor cell lines, with benzoxazolines showing the highest activity. Derivatives of estrone exhibited greater potency than those of androsterone, being up to 50‐fold more active than abiraterone, a steroidal anticancer drug. Live cell imaging of the lead compound combining estrone and a benzimidazoline residue revealed apoptotic events such as membrane blebbing, nuclear condensation, and cell shrinkage, suggesting potential utility for therapeutic applications.

We have synthesized a series of novel coumarin‐steroid and triterpenoid hybrids and evaluated their potential anticancer activity through molecular docking calculations and in vitro antiproliferative assays. These hybrids, derived from estrone and oleanolic acid, were linked via hydrocarbon spacers of varying lengths. Molecular docking studies against human aromatase revealed strong interactions, particularly for compound 11d , which exhibited significant binding affinity (−12.6308 kcal/mol). In vitro assays demonstrated that compounds 6b and 11d had notable antiproliferative effects, with GI ₅₀ values of 5.4 and 7.0 μM against WiDr (colon) and HeLa (cervix) cancer cells, respectively. These findings highlight the potential of these hybrids as novel anticancer agents targeting aromatase, warranting further investigation and optimization.

There is compelling evidence that incorporating a heterocyclic moiety into a steroid can alter its pharmacological and pharmacokinetic properties, driving intense interest in the synthesis of such hybrids among research groups. In this review, we present an overview of recent synthetic methodologies, spanning the period from 2000 to 2023, for the preparation of spiro heterocyclic steroids. The compounds surveyed encompass four-, five-, six-, and seven-membered heterocycles appended to various positions of steroidal backbones, with spirocycles containing oxygen, nitrogen, and sulfur atoms being predominant. The outlined synthetic procedures emphasize the pivotal steps for constructing the heterocycles, often accompanied by a detailed account of the overall synthesis pathway. The review encompasses innovative compounds, including bis-steroids linked by a spiro heterocycle and steroids conjugated to heterocyclic moieties containing three or more (hetero)cycles. Moreover, many compounds are accompanied by data on their biological activities, such as antiproliferative, antimalarial, antimicrobial, antifungal, steroid antagonist, and enzyme inhibition, among others, aimed at furnishing pertinent insights for the future design of more potent and selective drugs.